Abstract
When a moving object vanished, it is mislocalised toward the moving direction. Three experiments examined the effects of spin on the mislocalisation. The target stimulus was a circle with an axis bar (in its center). In the first experiment, the target moved horizontally from left to right and vice versa with a uniform velocity. Additionally, the target had a spin in (forward) or against (backward) the direction of motion. Observers' task was to point with cursor the vanished position of the target as accurately as possible. The results revealed that when observers fixated on the fixation mark forward displacement varied with the direction of spin, the larger displacement for forward spin. This suggested that the displacement was attributed to the internalised representational friction. On the other hand when observers pursued the target, the forward displacement was promoted by the spin itself (regardless of its direction). In the second experiment, the orientation of axis in the target circle was randomly changed in each frame. Forward displacement was still observed only in the condition in which observers pursued the target, indicating that mere axis action made the forward displacement. In the third experiment, the target was stationary while spinning and no displacement was observed, and so spin was considered to have no self-propulsion. The results of three experiments suggest that two kinds of motion, namely, orbit and spin, interact in visual short-term memory, the by-product of which is the mislocalization.